The question asks us to identify the pair of a crop and its leading producing State that is not correct. To accurately answer this, we need to verify the top producing states for each crop mentioned in the options. If all the given pairs are factually correct, then the appropriate answer would be "None of these".

Let's examine each option to determine the accuracy of the crop and its leading producing state pairing:

Rice Production in India

• Rice is one of India's most significant food crops, primarily cultivated during the kharif (monsoon) season. It thrives in regions with high temperatures and substantial rainfall.
• West Bengal is widely recognized as the largest rice producing state in India. Its fertile deltaic plains, favorable climate, and abundant water resources are highly conducive to extensive rice cultivation, making it the top producer nationally.

Wheat Production in India

• Wheat is another crucial cereal crop in India, typically grown as a rabi (winter) crop. It requires a cool growing season and bright sunshine during harvest.
• Uttar Pradesh consistently holds the position of the largest wheat producing state in India. The state's vast, fertile plains, coupled with well-developed irrigation systems, provide ideal conditions for high wheat yields.

Cotton Production in India

• Cotton is an essential commercial crop and a primary raw material for India's textile industry. It grows best in the black soil regions which are known for their moisture-retentive properties.
• Gujarat is the leading cotton producing state in India. The presence of extensive black soil (regur) areas and a climate suitable for cotton cultivation has established Gujarat as the largest producer.

Rape and Mustard Production in India

• Rape and Mustard collectively represent significant oilseed crops in India, vital for edible oil extraction. These crops are generally grown in semi-arid and temperate regions.
• Rajasthan is the foremost producing state for rapeseed and mustard in India. The state's diverse agro-climatic zones, particularly in its eastern parts, are highly suitable for the cultivation of these oilseeds, making it the largest contributor to India's rape and mustard production.

Comparison of Crop and Leading Producing States

Based on this comprehensive analysis, all the provided pairs—Rice : West Bengal, Wheat : Uttar Pradesh, Cotton : Gujarat, and Rape and Mustard : Rajasthan—are accurate representations of the leading producing states for their respective crops in India. Since none of the pairs are incorrect, the statement "None of these" correctly identifies that there is no incorrect pair among the given options.